The bell is the perfect symbol of the perfect meditation.
The bell is the unfabricated space of the mind.
The clapper is pure perception of the mind.
The clapper hitting the bell produces the sound.
The pure perception of the mind sitting in unfabricated space of the mind produces recognition of the real nature of mind. And that's what brings the famous realization everybody is seeking for.

That's what I invented to explain to a friend what is the perfect meditation, explained like this because he does not know the language we use in the Dharma and he has no theoretical knowledge of anything about meditation.